replace http client Requests to compatible Niquests

[Ousret]

Description

This PR effectively replace the http client Requests for Niquests. Niquests is a drop-in replacement for Requests that is no longer under feature freeze.

This new client support HTTP/2, and HTTP/3 by default and offers both sync and async interfaces. It supports all the latest shiny features you would expect from an http client.

If you were interested on merging, I will be thrilled to propose a followup PR that will propose a script that generate the async part of plex-client automatically.

This PR is a low footprint change. I did not change the "alert" part, based on WS, because there's something we can't support: "reusing existing socket instance". Would it be a breaking change according to you?

disclaimer: I maintain Niquests.

Type of change

Please delete options that are not relevant.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have added or updated the docstring for new or existing methods
• [x] I have added tests when applicable